<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<script>
			var arr = [12,21,23,21,12,21,21,12,14];
			for(var i=0;i<arr.length-1;i++){
				for(var j=i+1;j<arr.length;j++){
					if(arr[i]==arr[j]){
						arr.splice(j,1);
						j--;
					}
				}
			}
			console.log(arr);
		</script>
	</body>
</html>
